Using Apache POI 3.15 cells of type Boolean are formatted as "TRUE" or "FALSE" instead of "true" or "false" and this leads to generate an invalid drl that will raise compilation errors like the following

Rule Compilation error : [Rule name='Spreadsheet Example_11']
  rule_table/Rule_Spreadsheet_Example_11413427566.java (7:503) : FALSE cannot be resolved to a variable